Local spread of Tn1546-like element among three species of vancomycin resistant enterococci in an intensive care unit

Abstract

Introduction: In an intensive care unit (ICU) of the Emergency Center in the Clinical Center of Serbia, four species of vancomycin resistant enterococci (VRE) were isolated in a 17-month period mostly from blood cultures, including E. faecalis, E. faecium, E. raffinosus and E.gallinarum. Methodology: The relationship between isolates from each species was investigated by PFGE, and PCR experiments for detection of pathogenicity factor genes and van genes to determine the nature of each clone. A PCR-based method, using 10 primer pairs (p1/2-p19/20), was used to investigate the presence of the Tn1546-like structure. Results: PFGE indicated the presence of two different E. faecium clones, while the three other enterococcal species belonged to one clone each. Transposon typing revealed that isolates of E. raffinosus (4), E. gallinarum (4) and E. faecalis (3) yielded gene sequences identical to 10 primer pairs (p1/2-p19/20), suggesting the possibility of identical transposon-like structure in these species. Conclusions: The results of the study indicate probable horizontal spread of Tn1546-like structure in three species of VRE obtained from the same ICU.